Questions about building snow roof over deck

Discussion in 'General Home Improvement Discussion' started by SidecarBob, Sep 25, 2017.

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  1. Sep 25, 2017 #1

    SidecarBob

    SidecarBob

    SidecarBob

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    Background:
    I live in South Central Ontario and I have a 6' x 20' deck at the back of the 23 year old brick veneer house that was built by the contractor who built the house. It is approx. 42" above grade and supported by a ledger/joist attached to the wall and four 4x4 posts right at the outer edge. The posts are set on bricks, about 4-5" below grade and end at the railings, approx. 43" above the floor. It is framed with 2x6s (all end nailed - no joist hangers) and the floor is 2x4s.

    We have always shovelled the deck in winter so that the laundry room door and patio door could be used as emergency exits (fortunately never needed so far). A few years ago we had the roof done with steel shingles and now the snow slides off regularly, filling the deck. One morning last April I woke to 6" of snow on the deck and an hour later heard the "avalanche and the snow was almost up to the deck's railing (that time I only cleared from the laundry door to the stairs - it all melted within a few days anyway).

    The project:
    I have been talking about putting a roof over the deck to carry the snow past it when it slides off for years and always forgot when I wasn't shovelling it off but we had a heat pump installed last year and I want to get to the project before it is damaged by the snow sliding onto it. The heat pump is on legs on the ground (on patio stones), right near the end of the deck so I figure if I build the roof 4' longer than the deck it will protect the heat pump too.

    Question #1:
    There is 89" between the deck floor and the soffit.
    Assuming the framing doesn't overhang the edge of the deck (the steel can go an inch or so past), 2x6 framing and an inch + for corrugations in the metal, if there is 72" from the floor to the top of the roof at the outer edge the bottom of the edge of the edge joist/facer will be about 65" above the floor and any lower will render the deck useless.
    That means that the pitch would be approx. 1 in 4.25 (2.83 in 12). Is that enough pitch for straight steel panels to shed snow?

    Question #2:
    I really don't want to dismantle the deck any more than I have to and I don't want to pour footings. Can I cut the bottom end off of each of the existing posts and put deck blocks under them?

    Question #3:
    If I do that would I be better to extend the posts to support the outer edge of the roof by
    A) Extending them with lap joints bolted through (not my favourite idea)
    B) Sandwiching the original posts between 2x4s (or 2x6s?) (not the best looking solution)
    C) Cutting the posts off at floor level and building a 2x4 (2x6?) frame wall to support the roof. (I am leaning to this idea.)

    Question #4:
    If I build a framed wall I would still need an additional post for the part of the roof that would be over the heat pump. Would I need to build the framed wall all the way to that post or can it end at the end of the deck?

    Question #5
    The existing outer edge joist is currently a single 2x6. I expect that if I build a framed wall on top of it I would need to add material for it to bear the load. If I did that I would want the added piece to extend to the post supporting the end of the roof above the heat pump to stabilize it.
    Can I just nail another 2x6 (2x4?) to the existing one for that?

    That's all for now. I'm sure I will find other questions as I figure out what I need to order for this...
     
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  2. Sep 25, 2017 #2

    nealtw

    nealtw

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    You get away with the deck sitting on blocks because the deck can flex when the ground freezes and that may pull nails from the ledger.
    You do not get so lucky with the roof. You would want footers and piers to support the roof.

    For starters while you think it over I would build a dog house roof over the heat pump to protect that and keep the snow away from it.
    You could just add a skirt roof to move a snow a little further from the door.
    Or snow stopper thingies they put across the steel roof to slow the snow slide.
     
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  3. Sep 25, 2017 #3

    bud16415

    bud16415

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    The first problem I see is that your deck is connected to the house on one side with a ledger and the other side and center posts are free floating. We live just across the lake from you and have similar winters and maybe even more snow. My deck is built free floating but not connected to the house so with freeze thaws it can move independent of the house that has deep footings and does not move. You will be seeing maybe an inch of movement on one side of your deck and zero on the other if I’m reading this right and that movement will work on those nail connections until something fails.

    If the deck is 23 years old that is a good sign that the structure is somehow working configured like this. Replacing the bricks with the precast footings won’t really change much and should be no worse than the bricks I think.

    I just had a steel roof put on this summer and I have a similar situation where the house roof will shed snow to the deck roof. I will be watching this closely as I didn’t have them put the snow retainers on but I have a box of them if needed. Time will tell.

    What pitch is on your main roof and what pitch will be on the new deck roof?

    You might want to think about the snow retention clips as well.
     
  4. Sep 25, 2017 #4

    SidecarBob

    SidecarBob

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    Even though the house is fairly new and built to modern standards I like the idea of the snow coming off the roof on its own. We haven't been having as much snow in recent years but there is always the chance of a heavy year. Which adds up to I would rather not add the stoppers if I don't have to. BTW: We had the eaves troughs done at the same time as the roof and the sliding snow doesn't seem to have loosened them at all. That was 9 years ago when the "25 year" asphalt shingles failed.

    FWIW, I was under the deck re-caulking a couple of windows last week and the framing seems to be tightly together so the nails don't seem to have pulled out. So far. I wonder if that has anything to do with the bricks that the posts sit on being a few inches below grade?

    I am thinking about the precast footings for 2 reasons: 1) to support the extra weight (they would have about 2-3 times the area) and 2) The outer edge has a bit of a sag. Most people don't notice the sag but I inherited my Dad's eye for straight & level (he was a carpenter/cabinet maker for most of his career) and it bothers me. This would be a good way to get it back up to level.

    The house roof has a 7 in 14.5 pitch (1 in 2.1) and if I build the deck roof as described above it would have 1 in 4.25 or about half the pitch of the house roof. That is my big concern because if it isn't enough there is no point doing it unless I rip out the whole deck and rebuild lower.

    I think Erie gets more snow than we do. We are in what some people refer to as Ontario's "banana belt", getting about half the snow that people living half an hour's drive north or south of here get and a lot less than they get near Lake Ontario. I think it is because even the biggest lake near here (Lake Simcoe) freezes over completely most years so there is nowhere west of us for the wind to pick up moisture to drop on us.
     
  5. Sep 25, 2017 #5

    nealtw

    nealtw

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    Perhaps there are footing under the deck and some one raised out of the dirt with bricks. They will be 3 1/2 to 4 ft in your area

    Pitch is understood better if it si stated as rise over 12" as in 6/12 or 9/12.
     
  6. Sep 25, 2017 #6

    SidecarBob

    SidecarBob

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    Sorry. The house roof is 5.75/12 and without lowering the deck its roof would be 2.83/12.

    I stopped digging when I found the bricks. I could dig a bit deeper and see but I doubt that there is any concrete under there. The house has been in our family since built (we inherited it from my parents); I know I haven't ever dug around where the posts go into the ground or raised the level of the soil in the 17 years we have lived here and I'm pretty sure my Dad didn't either.

    I could dig down a bit more to see what's under the bricks but its 30c out there with the sun hammering down on the back of the house so it will have to wait until it starts to cool off.
     
  7. Sep 25, 2017 #7

    nealtw

    nealtw

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    Get a 4 ft piece of rebar and pound it in on angle and see if it will go under the brick or run into something solid.
     
  8. Sep 25, 2017 #8

    SidecarBob

    SidecarBob

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    And under the brick is.... Drumroll please... Gravel
     
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  9. Sep 25, 2017 #9

    joecaption

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    Post a picture so we can see what your seeing please.
     
  10. Sep 25, 2017 #10

    nealtw

    nealtw

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    My story stays the same. you would need footers
     
  11. Sep 25, 2017 #11

    SidecarBob

    SidecarBob

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    Joe, do you mean what I see in the hole or overall?

    Not that it would make a lot of difference anyway. This forum won't let me upload pics directly and I'm not going to use Photobucket :(

    Neal, if I have to put in footings I won't be doing it. I'm not up to digging 5 holes a foot across and 4' deep by hand and using a post hole auger would mean removing the deck to get it into place.
     
  12. Sep 26, 2017 #12

    nealtw

    nealtw

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    I would dig the holes 1 ft outside the deck and leave the deck alone.
    5 holes, how wide?
     
  13. Sep 26, 2017 #13

    SidecarBob

    SidecarBob

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    I don't understand. The last time I rented an auger (a couple of decades ago at another house) I was able to use it for the holes out in the open but the one close to the wall had to be dug by hand. And if I did manage to dig the holes a foot out from the deck how would the footings support the posts?

    BTW: Only 4 of the holes would need to be under the deck for the existing posts. The 5th one would be out in the open by the heat pump.

    Joe: I just realized that I can attach images so again what do you want a pic of?
     
  14. Sep 26, 2017 #14

    nealtw

    nealtw

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    There are new augers. You dig a 8" hole do your best to make the vary bottom a little bigger fill it with concrete and place post saddle in the top. and build the roof off that.

    It is to bad you didn't do this before the steel roof went up, a shed roof could have met the main roof a little further up.
    I guess you could put 12 ft between 6x6 posts and 3 ply 2x10 beams , but slope may be a problem
     
  15. Sep 26, 2017 #15

    SidecarBob

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    I don't know if putting in posts for the roof outside of the existing deck would work. I'll have to think about that.
     
  16. Sep 26, 2017 #16

    nealtw

    nealtw

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    I hate the look but if you put the rafters to the beam in hangers instead of running over top, you gain a little height .
    Minimum ceiling height is 80"
     
  17. Sep 26, 2017 #17

    nealtw

    nealtw

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    How ugly could it be:p

    images39.jpg
     
  18. Sep 27, 2017 #18

    Sparky617

    Sparky617

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    For a roof over your deck you could do something like this: http://www.skylifthardware.com/ This would allow you to have the pitch you want/need without having the deck roof come down to 6 feet at the end of the deck.

    To keep the snow from your roof from sliding onto your deck you could use roof snow guards: http://www.metalroofsnowguards.com/
     
  19. Sep 27, 2017 #19

    Sparky617

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    That's pretty ugly.
     
  20. Sep 27, 2017 #20

    SidecarBob

    SidecarBob

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    Sparky, I think the Skylift setup is pretty ugly too and besides, the snow would slide under it so there would be no advantage for me.

    Neal, I have been thinking about it while I worked on my other project yesterday (sanding furniture in this heat is not fun and I ended up having to take my ROS apart to clean the commutator and brushes when it stopped working). If I attached the deck roof under the soffit and put the posts farther out that would require the edge of the roof to be even lower to have any amount of pitch so I don't want to do that either.

    Going back to my original questions, if I built it the way I proposed would there be enough pitch? If there wouldn't the project is not feasible.

    As you said, it would have been easier to extend the roof when we had the steel shingles installed but that was a long time ago and we didn't know that much more snow would slide off than before. This has to be a relatively quick & simple project that I can do mostly on my own so digging into the existing roof to attach it there is not going to happen.
     

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